In the performance of exercises for fitness or therapeutic purposes, proper positioning of a person's body parts is important. Improper positioning can result in inefficient exercise or, worse, potentially serious injury.
As a particular example, the single-leg lunge (both stationary and ambulatory) and single-legged and two-legged squat, are important movements in the rehabilitation of several lower extremity ailments, injuries, and post-surgical interventions. These movements are also important for developing lower extremity muscles, such as the gluteus, quadriceps, hamstrings, gastrocnemius, and others. Flexion of the knee joint while the foot is firmly planted on the ground is a common biomechanical movement in the daily lives of humans with at least one fully functional leg. When the knee is flexed and the center of mass of the body is lowered, a significant amount of muscle activation is required throughout the leg and with the trunk or core.
Single-leg lunges involve a down-and-up motion with the back foot planted on the ground. Ambulatory lunge sequences involve lunging forward, transferring one's weight to the front foot, bringing the back foot forward to the side of the lead foot, and then repeating the sequence with the opposite leg. These exercises, as well as two-legged squats, involve keeping the person's center of gravity far enough posteriorly that the knee of the lead leg or, for two-legged squats, both knees, does not cross above and over the vertical plane of the great toe.
When the knee crosses the vertical plane of the toes, a significantly higher amount of stretching, and stress, occurs at the patella tendon. This higher stress can cause unnecessary injury or pain with the knee joint and surrounding muscles and ligaments. In order to prevent injury, patients, athletes, or other individuals are encouraged to keep the gluteus as far back as possible, preventing the kneecap from crossing the vertical plane of the toes.
Keeping the kneecap behind the vertical plane of the toes is particularly important during the walking lunge. The walking lunge closely represents the movement involved in typical daily activities. In addition, the walking lunge involves core stabilization and lower extremity muscle activation. The dynamic movement pattern associated with the walking lunge is frequently prescribed for patients and athletes to perform on a regular basis on their own, when verbal cues and guidance from trained professionals is not available.
Accordingly, it would be beneficial to have a device that can be used during a walking lunge sequence or during similar movement patterns in which the front knee is flexed to approximately 90° and in which proper form is required. Preferably, such a device should be light weight and should be easy to secure to a foot.